El Niño appearances tied to civil conflicts in tropical countries

Political conflicts are extremely complex, and we almost never understand all the factors that are involved in their timing, the course they take, and their eventual outcome. In this week’s Nature, a paper suggests a new variable to consider: the climate. According to researchers from Columbia and Princeton, there is good evidence that global climate variations can play a role in the onset of civil conflicts.

The El Niño-Southern Oscillation cycle, known as ENSO, is a climatic pattern that repeats about every 5 years. Variations in water temperatures and air pressure in the Pacific Ocean cause El Niño years to be warm and dry, while La Niña years are cooler and wetter. These oscillations are felt most strongly in tropical countries, while mid-latitude areas are much less affected.

The authors of the study hypothesized that these cycles might play a role in the onset of civil conflicts. Although some research has been done on the correlation between climate and conflict, methodological difficulties and inconclusive results have caused lots of confusion. Climate studies are difficult because there is no Earth we can control to experiment with; we are stuck examining global patterns with few controls. However, in this study, ENSO provides a convenient experimental setup: volatile El Niño years provide a “treatment” group, while calmer La Niña years serve as a control.

175 countries were included in the dataset, including 93 tropical countries that are highly prone to the effects of El Niño and 82 other countries that are weakly affected by ENSO. Countries were classified as experiencing "conflict onset" in a given year if more than 25 people had died as a direct result of a new political dispute between two groups. Conflicts from 1950 to 2004 were included. Then the researchers calculated the annual conflict risk (or ACR) for both the tropical countries and the weakly affected countries. The ACR is the probability that a randomly selected country from the group experienced conflict onset in a particular year.

For the countries that aren’t highly affected by ENSO, such as Greece, Afghanistan, and Sweden, the ACR was about 2 percent in both El Niño and La Niña years, indicating that these climate cycles are unlikely to affect civil conflict in these countries. However, the ACR for tropical countries such as Australia, Sudan, and Trinidad doubled during El Niño years, increasing from 3 percent to 6 percent. From their analyses, the researchers concluded that the ENSO cycle may have affected 21 percent of civil conflicts since 1950.

The results are remarkably robust; the researchers repeated the analysis with various types of statistical models and with different ENSO indices, and their conclusions remained the same. Furthermore, the results held up even when high-conflict countries were excluded from the dataset, and when other variables, such as a country's age structure, income growth, and agricultural reliance, were included in the analyses.

Two additional findings were particularly intriguing. Many of the conflicts affected by ENSO are particularly deadly recurring conflicts. By changing the requirement for the length of "peaceful periods" between conflicts, the researchers found that the relationship between ENSO and large conflicts decreased. Additionally, low-income countries were the hardest hit by El Niño years, indicating that poorer countries are particularly sensitive to ENSO patterns.

Although the relationship between ENSO and civil conflicts is quite clear, the reasons behind this correlation are still not understood. Warm, dry El Niño years might decrease agricultural output, stressing a country’s resources and increasing food prices. ENSO patterns affect the frequencies of natural disasters, such as hurricanes and cyclones, which put countries at risk for upheaval. Extreme conditions can also cause psychological stress and alter human behavior. Finally, ENSO is a widespread phenomenon, and may cause suboptimal conditions on a large scale.

In order to use the results of this study to predict or alleviate conflicts, we need to better understand the mechanisms driving the relationship between climate patterns and political conflict.

31 Reader Comments

This isn't a terribly groundbreaking theory. A bunch of largescale civilization events have been tied to global/regional weather phenomenons. The "Age of Exploration", the American and French Revolutions, all linked to weather events. And it's not hard to see why. Weather affects everything from food production/distribution to a person's comfort level. Couple an empty stomach with a person being too hot or too cold, and they're going to be just a tad cranky.

According to researchers from Columbia and Princeton, there is good evidence that global climate variations can play a role in the onset of civil conflicts.

El Nino concerns weather trends and events. Climate change, aka "global warming," is supposedly *not* about weather events at all. At least, man-made GW proponents in the Ars forums keep trying to assure everyone that climate and weather should not be confused. Yet, it seems something is confused in this article... Or is it?

It strikes me that man-made GW proponents will stop at nothing in order to provide justification for rafts of laws and regulations designed to curb "man-made global climate change." Generally, these have to do with the allocations of possibly hundreds of billions of dollars of government funds to private industries to develop so-called "green" technologies designed to avert "the coming catastrophe(s)." (TM)

Attempting to tie civil unrest around the world to "climate change" seems to me just a clever way of trying to inject one more "bad outcome" into the "man-made GW" stew pot. There's a simple truth the "man-made GW" proponents are loathe to discuss, and that is: we cannot control the weather. That is, we know of no mechanism within the control of man, by way of any action any government might legislate, that would serve in any capacity whatever to control and regulate the weather. El Nino causes weather events.

But the propaganda has subtly instilled the idea into the popular psyche that "climate," otoh, is something man can control and regulate, and the way he does that is by way of government fiat and government expenditure into "green" industries controlled by the select few, of course (as that is the whole idea.) Thus we see something as shoddily unscientific as El Nino weather events being called "Climate Change" in a so-called scientific journal. Caveat emptor, but it surely appears as if some man-made GW proponents are becoming desperate to peddle their wares.

According to researchers from Columbia and Princeton, there is good evidence that global climate variations can play a role in the onset of civil conflicts.

El Nino concerns weather trends and events. Climate change, aka "global warming," is supposedly *not* about weather events at all. At least, man-made GW proponents in the Ars forums keep trying to assure everyone that climate and weather should not be confused. Yet, it seems something is confused in this article... Or is it?

It strikes me that man-made GW proponents will stop at nothing in order to provide justification for rafts of laws and regulations designed to curb "man-made global climate change." Generally, these have to do with the allocations of possibly hundreds of billions of dollars of government funds to private industries to develop so-called "green" technologies designed to avert "the coming catastrophe(s)." (TM)

Attempting to tie civil unrest around the world to "climate change" seems to me just a clever way of trying to inject one more "bad outcome" into the "man-made GW" stew pot. There's a simple truth the "man-made GW" proponents are loathe to discuss, and that is: we cannot control the weather. That is, we know of no mechanism within the control of man, by way of any action any government might legislate, that would serve in any capacity whatever to control and regulate the weather. El Nino causes weather events.

But the propaganda has subtly instilled the idea into the popular psyche that "climate," otoh, is something man can control and regulate, and the way he does that is by way of government fiat and government expenditure into "green" industries controlled by the select few, of course (as that is the whole idea.) Thus we see something as shoddily unscientific as El Nino weather events being called "Climate Change" in a so-called scientific journal. Caveat emptor, but it surely appears as if some man-made GW proponents are becoming desperate to peddle their wares.

The article never discusses, or even mentions, 'climate change' or 'global warming'. The very heart of this article is a phenomenon unchanged over the period of the study, or the study would be invalid.

Each El Nino is weather. A long term pattern of El Ninos and La Ninos is climate. A paper on the correlation between the cycle of El Ninos and politics is a Doctorate! <G>

Perhaps reading the article BEFORE posting would reduce your frustration.

Actually the messed silverware is fitting giving the study contents, and the image chosen for this article probably smartly deliberate.

Even the title seems out of place. Should be "civil conflicts in tropical countries tied to El Niño appearances". I don't normally like to see too much into things, but if Kate Shaw feels even a bit sick as I do about this inane study, both title and image are marvelously chosen.

Anecdotal, but weather does seem to have an effect on crime/etc. Ask police, they'll say nights of the full moon are worse (probably because folks can see better to walk around at night) and, of course, bad weather nights have less crime (don't want to do crime and be miserable and wet while doing it).

So, we are in the midst of the relative, calm, cool tranquility of a La Nina in the tropical climes. Trust me, I just returned from Galapagos and it was never hotter than 82 degrees.

In Texas, OK, NM, LA and AR however, we are frying in unheard of temperatures and drought due to La Nina. I found it interesting that all of the naturalists in Galapagos were down on El Nino and really considered La Nina to be the natural state of things. Meanwhile, I held the exact opposite feelings. El Ninos are times of relative cool, wet and abundance for the south central area of the US.

And I just don't get this theory at all. It's way too freakin' hot to throw a revolution right now.

Correlation does in fact imply causation. While correlation does not prove causation, it seems that too many folks have decided to turn that around and think that now correlation denies causation. In practice, finding correlation is often used to guide science in looking for causation. In this case, the correlation between ENSO and civil conflict does imply some level of causation. And it's certainly reasonable to look at the ways ENSO might cause civil conflict before looking into ways that civil conflict causes ENSO. What is not reasonable is to assume that the correlation means nothing and no effort should be expended looking into possible causations between the two.

On the right track. Correlation CAN imply causation, but it doesn't conclusively demonstrate causation. As you mentioned though, correlation means you should investigate further to see if you can determine a link to causation, and it likely implies at least casual causation.

A fat man dying from a heart attack is likely because they were overweight. However, that fat man could have died from an enlarged heart, a heart valve defect, poisoning, etc without any of those being caused by being massively overweight. Even broad trends (coorelation) can be unrelated to causation, that tends not to be the case, but it is possible and does happen.

Anyone who denies the subtext is about climate change is being disingenuous at best.

Quote:

Although some research has been done on the correlation between climate and conflict, methodological difficulties and inconclusive results have caused lots of confusion. Climate studies are difficult because there is no Earth we can control to experiment with; we are stuck examining global patterns with few controls. However, in this study, ENSO provides a convenient experimental setup: volatile El Niño years provide a “treatment” group, while calmer La Niña years serve as a control.

Actually, in "Guns, germs, steel", Jared Diamond discuss some evidence that El Niño induced droughts in Australia on such a regular basis that it actually hampered aborigens from setting up a society which would not be hunter-gatherer based.

Roots of more than a few of the tribal wars which ravaged Africa even in recent times can often be found in fights over diminished food supplies.

If we can link in a scientific maneer emigration from european countries (such as Ireland) to the USA at times of famines caused by global weather disruption caused by volcanic eruptions, isn't the hypothesis not worth investigating ?

Actually, in "Guns, germs, steel", Jared Diamond discuss some evidence that El Niño induced droughts in Australia on such a regular basis that it actually hampered aborigens from setting up a society which would not be hunter-gatherer based.

Roots of more than a few of the tribal wars which ravaged Africa even in recent times can often be found in fights over diminished food supplies.

If we can link in a scientific maneer emigration from european countries (such as Ireland) to the USA at times of famines caused by global weather disruption caused by volcanic eruptions, isn't the hypothesis not worth investigating ?

Being a casual observer, postulater and theorizer trying to talk shop with staunch scientists is like being an inquisitive schoolyard kid questioning a nun with a ruler. Your enthusiasm will quickly get smashed in the knuckles. Books like that, and theories like that are interesting. But you're going to get folks poo-poo'ing on you for lack of scientific evidence, bean counting or over-speculation. However, I think you make some good points. Then again, I was always more fascinated by the theorizing of science than the lab work.

The short of it is: (dromroll please) Hot people fight more. Yeah this isn't new. It's been a pretty well understood phenomena for a while now. Relating it this directly to political unrest, that may be new.

Kate Shaw Yoshida / Kate is a science writer for Ars Technica. She recently earned a dual Ph.D. in Zoology and Ecology, Evolutionary Biology and Behavior from Michigan State University, studying the social behavior of wild spotted hyenas.